THE PROBLEM AS DESCRIBED IN AN IM CHAT:
(Discussing the patterns ExAxF and ExA-F, and other similar ones.)
[03:40] (You): Yes. I think a rule just has to be clarified a bit, one way or the other.
Trainer: yes...I think the question is rule 7 about shortest way
Trainer: you have to better clarify when it can be applied please
Trainer: we usually apply that rule between 2 small cirles...H-F of HxF for example
Trainer: but we have to walk a large part of G in that way
[03:46] (You): You really should NEVER have to walk more than just a little bit of a circle that is not named in the pattern (except the Center, of course).
Trainer: perfect
Trainer: the only case where we can apply that rule is between a big and a small circles near each other...for example A-H
Trainer: in that case we don't need to walk around the center
Trainer: because the same problem is between B and D, D and F, F and H, H and B...so I don't know where that rule is applicable
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IT LOOKS TO ME LIKE RULE 7 IS THE PROBLEM:
"7. All turns have to be done smoothly. To do that, the pony is permitted to use a small piece of a large circle to make a smooth curve."
The trouble is that we don't define "a small piece." (Up in rule 2 we say "a bit of a circle"--same problem.)
So we have to say either "No more than 1/4 of a large circle" or "No more than 1/8 of a large circle" depending on which way we want the rule to go.
The problem we looked at was ExA-F (or ExAxF; same problem). We start this way:
Clockwise around E, and then clockwise around the center circle (using 1/8 of G to make the smooth transition to the center circle), then Counterclockwise around A.
SO now we have two options:
1) Follow A all the way to the center circle, go around it clockwise, use 1/8 of E to make the smooth transition to the straight line OR
2) Follow A just to G, and use 1/4 of G to get to the straight line.
THEN use 1/8 of G to make the smooth curve (in the case of -F) or 1/8 of E (in the case of xF).
THE PROBLEM IS that we also have Rule 8: "Always walk the pattern in the shortest way possible." That points to Option 2 being the preferred one. But walking a full 1/4 of the way around a circle just to make a smooth curve seems very excessive. (And if you are doing ExA-F, you're doing 3/8 of the "G" circle--almost halfway--without "G" being named in the pattern at all.)
FIRST, I thought the answer was to change Rule 7 to read:
"7. All turns have to be done smoothly. To do that, the pony is permitted to use no more than 1/8 of a large circle to make a smooth curve."
...and also replace in Rule 2 "a bit" with "no more than 1/8".
But on March 10, Trainer Muse pointed out that for a simple pattern like CxF, that rule change would require going all the way around the center circle to avoid using 1/4 of circle E; and you would STILL end up using 1/4 of E, just in two parts with the center circle in between. WAY too complex.
So perhaps the rule change is this instead:
"7. All turns have to be done smoothly. To do that, the pony is permitted to use part of a large circle (even one not named in the pattern) to make a smooth curve."
and in Rule 2, replace "a bit of a circle" with "part of a large circle"
Open for comments! (March 10 2017)